The rapid diffusion of Wireless Local Area Network (WLAN) access and the increasing demand for WLAN coverage is driving the installation of a very large number of Access Points (AP). The most common WLAN technology is described in the Institute of Electrical and Electronics Engineers IEEE 802.11 family of industry specifications, such as specifications for IEEE 802.11b, IEEE 802.11g and IEEE 802.11a. A number of different 802.11 task groups are involved in developing specifications relating to improvements to the existing 802.11 technology. The IEEE 802.11v task group has developed a Wireless Network Management draft specification, entitled “Standard for Information Technology—Telecommunications and Information Exchange Between Systems—LAN/MAN Specific Requirements, Part 11: Wireless Medium Access Control (MAC) and physical layer (PHY) specifications, Amendment v: Wireless Network Management,” IEEE 802.11v.D0.03, May 2006.
As another example, some wireless networks are based upon the Distributed Medium Access Control (MAC) for Wireless Networks industry specifications of the WiMedia Alliance, for example. For example, the WiMedia network protocol adaptation (WiNet) layer is a protocol adaptation layer (PAL) that builds on a WiMedia ultra-wideband (UWB) common radio platform to augment the convergence platform with TCP/IP services. A number of working groups are working to improve on this technology.
An example standard, for example, the Distributed Medium Access Control (MAC) for Wireless Networks of the WiMedia Alliance, defines a distributed medium access control (MAC) sublayer for wireless networks, and further specifies a wireless network structure that does not require an existing infrastructure for communication such as, for example, a WiMedia ultra-wideband (UWB) network.
Categories of example applications considered for such an example standard may include portable electronic devices intended to be carried by a user, home electronics equipment, and personal computers and peripherals. Example portable electronic devices may have specific requirements to support mobility and good power efficiency. Devices such as home electronics and computers may not be as mobile, and not as sensitive to power efficiency as such portable electronic devices.
With efficient power management great savings can be achieved in infrastructure networks. Traffic for mobile stations may pass through access points, so the access points provide ideal locations to buffer traffic. Access points may be aware of associated mobile stations, and a mobile station may communicate its power management state to its access point. Furthermore, access points may remain active at all times; thus access points may play a key role in power management on infrastructure networks. An access point may know the power management state of every station that has associated with it, and thus the access point may determine whether a frame should be delivered to the wireless network because the station is active, or whether the frame should be buffered because the station is in a powersave state. In order to enable mobile stations to receive the data waiting for them, an access point may announce periodically which stations have frames waiting for them. The periodic announcement of buffer status may also contribute to the power savings in infrastructure networks, as powering up a receiver to listen to the buffer status may require far less power than periodically transmitting polling frames. Thus, a station may only need to power up the transmitter to transmit polling frames after being informed that there is a reason to expend the energy.
A conventional IEEE 802.11 network may, for example, provide a fixed power save scheme to be used by broadcast and different multicast services. The scheme may, for example, define a fixed listen interval for stations (STAs) or mobile stations in the network. For example, an access point (AP) may buffer all the broadcast and multicast traffic and after a specific Delivery Traffic Indication Map (DTIM) beacon frame (e.g., a DTIM may be included in every nth beacon frame) the AP may automatically deliver all the buffered broadcast and multicast traffic. However, different broadcast and multicast services may have very different service characteristics, and thus having only one static scheme in a wireless local area network (WLAN) level may provide little flexibility. Example services may vary from basic broadcast services such as Address Resolution Protocol (ARP) or Dynamic host Configuration Protocol (DHCP), which may have low bit rates (e.g., needing a long listen interval), to different multicast streaming services (e.g., audio, video, etc.) having high bit rate requirements (e.g., needing a shorter listen interval).
However, current fixed schemes may provide only a single bit (e.g., an association identifier (AID) 0 bit in a TIM field) for an AP to indicate the existence of buffered broadcast and/or multicast data. Thus, a receiving STA may not know whether the buffered data is broadcast or multicast, and more particularly the STA may not know whether the buffered data is associated with a multicast service for which the STA desires to receive the data. Thus, the STA may need to switch to an awake state and receive data, even when the data is not intended for this particular STA, thus consuming energy to receive unneeded data.
Techniques for determining flexible configurations for broadcast and multicast transmission may thus advantageously improve performance of stations receiving broadcast and/or multicast information.